Figure 4.

Example plots illustrating control system performance during the eight walking bouts. Upper panel: SFM data (black) and control system set point (orange), both in mm. A consistent scale is not used across bouts so that the shapes of the curves are clearly visible. The SFM is closer to the set point at the end of the bout than at the outset, demonstrating that the control system is performing well. Lower panel: IAE in mm plotted over the course of each bout. The shape of the IAE curves over time, a rise and maximum followed by a decrease to a stable value, is typical for a properly functioning engineered control system.